One or more embodiments relate generally to the field of organic light-emitting diode (OLED) displays. More particularly, one or more of the embodiments relates to a method and apparatus for warpage compensation of a display panel substrate assembly.
Traditional liquid crystal displays (LCDs) are utilized as conventional display devices. Unfortunately, LCDs require backlighting, as well as diffusers and polarizers, since LCD displays are not self-luminous. Furthermore, the backlighting is generally provided by bulky and environmentally undesirable mercury lamps, which consume inordinate amounts of power. Likewise, the lumination within LCDs often generates undesirable amounts of heat and causes electrical interference within attached electronic devices. As a result, LCDs generally require substantial space and are often quite heavy.
In contrast, organic light-emitting diode (OLED) technology generally enables full color, full motion, flat panel displays, with a level of brightness and sharpness not possible with traditional LCDs. Moreover, unlike traditional LCDs, OLEDs are self-luminous. As a result, flat panel displays utilizing OLEDs do not incur many of the problems suffered by traditional LCDs.
An OLED structure, which is utilized to enable an OLED display device generally includes organic carbon-based film layers between two charged electrodes. A first electrode is commonly a metallic or conductive cathode, while a second electrode is commonly a transparent anode, generally made of glass. The organic film layers may comprise a hole injection layer, a hole transport layer, an emissive layer and an electron transport layer.
In operation, a voltage potential is applied to an OLED structure to provide rumination within the OLED display device. When the charge is applied, the injected positive and negative charges within the OLED recombine in an emissive layer in order to create electroluminescent light. As a result, OLED displays emit light, in contrast with conventional display technologies, such as LCD displays, which modulate transmitted or a reflected light.
An OLED structure may also include a ceramic panel and a conductive adhesive contact. In order to construct panels, such as OLED displays, some kind of substrate, such as a ceramic, organic or metallic plate, is required. As such, the substrate enables assembly of an OLED panel that is constructed of glass or organic film in order to enable connection to an electric circuit. However, in order to enable full motion flat panel displays, a warpage tolerance/coplanarity specification value required of selected substrates is generally less than 30 microns per inch (micron/inch).
Unfortunately, the coplanarity specification required for OLED flat panel displays drastically increases the cost to manufacturers of OLED displays. In order to address the warpage tolerance coplanarity specification requirements, manufacturers of conventional OLED displays generally utilize higher cost ceramic substrates. Otherwise, the manufacturers utilize special treatments (polishing), which are applied to ceramic substrates to reduce the warpage level of the substrate to conform to required tolerances. Consequently, conventional processes for enabling flat panel OLED display construction significantly increase the costs of substrate material.